This document uses the following technical terms:
A segment is the unit of end-to-end transmission in the TCP protocol. A segment consists of a TCP header followed by application data. A segment is transmitted by encapsulation in an IP datagram.
This term is used by some application layer protocols (particularly SMTP) for an application data unit.
A [UDP] datagram is the unit of end-to-end transmission in the UDP protocol.
A host is said to be multihomed if it has multiple IP addresses to connected networks.